Atrophy of the left cricoarytenoideus muscle  is characteristic of  laryngeal hemiplegia (roaring). 

     As can be seen in this image, the left muscle is thinner and therefore appears lighter in color when compared to the right side. 

The difference is especially apparent at the site of insertion on the muscular process (*).  The insertion of the left muscle is fibrous and thin, while that of the right muscle is bulbous and thick.